<p>We have developed an extension of the inert doublet model in which the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi></math> phases in the weak sector are generated from one-loop level corrections mediated by dark fields, while the strong <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi></math> phase remains vanishing at three loops. In this framework, the tiny masses of the active neutrinos are produced through a radiative inverse seesaw mechanism at a two-loop level, the masses of the first and second families of Standard Model (SM) charged fermions arise from a one-loop level radiative seesaw mechanism, and the third generation of SM charged fermion masses are generated at tree level. We have demonstrated that the proposed model successfully accounts for SM fermion masses and mixings. The radiative nature of the seesaw mechanisms is attributed to preserved discrete symmetries, which are required for ensuring the stability of fermionic and scalar dark matter candidates. The preserved discrete symmetries also allow for multicomponent dark matter, whose annihilation processes permit one to successfully reproduce the measured amount of dark matter relic abundance for an appropriate region of parameter space, which has been shown to be compatible with current dark matter direct detection limits. Besides that, we explore the model’s ability to explain the 95 GeV diphoton excess observed by the CMS Collaboration, showing that it readily accommodates this anomaly. We also have shown that charged lepton flavor violating decays acquire rates within the current experimental sensitivity.</p>

Vietnam

D.T. Huong

Chile

A.E. Cárcamo Hernández

H.T. Hung

T.T. Hieu

Nicolás A. Pérez-Julve

N.T. Duy

Extended inert doublet model with low scale seesaw mechanisms

The lepton flavor violating decay of the Standard Model-like Higgs boson (LFVHD), h→μτ , is discussed in seesaw models at the one-loop level. Based on particular analytic expressions of Passarino–Veltman functions, the two unitary and 't Hooft Feynman gauges are used to compute the branching ratio of LFVHD and compare with results reported recently. In the minimal seesaw (MSS) model, the branching ratio was investigated in the whole valid range 10−9–1015 GeV of new neutrino mass scale mn6 . Using the Casas–Ibarra parameterization, this branching ratio enhances with large and increasing mn6 . But the maximal value can reach only order of 10−11 . Interesting relations of LFVHD predicted by the MSS and inverse seesaw (ISS) model are discussed. The ratio between two LFVHD branching ratios predicted by the ISS and MSS is simply mn62μX−2 , where μX is the small neutrino mass scale in the ISS. The consistence between different calculations is shown precisely from analytical approach.

N.H. Thao

L.T. Hue

N.T. Xuan

Lepton flavor violating Higgs boson decays in seesaw models: New discussions

In calculating one-loop contributions to amplitudes of the lepton-flavor violating decays of the neutral Higgses (LFVHD) to different flavor charged leptons, the analytic expressions can be written in term of PassarinoVeltman functions. Then, they can be computed numerically by LoopTools [ 1 ]. Another approach is using suitable analytic expressions established for just this particular case. We compare numerical results obtained from LoopTools and those computed by different expressions that have been applied recently. Then we derive the preferable ones that are applicable for large ranges of free parameters introduced in extensions of the standard model. For illustration, the LFVHD in a simple model, which has been discussed recently, will be investigated more precisely.

K.H. Phan

One-loop contributions to neutral Higgs decay h

The masses and signals of the production of doubly charged Higgses (DCH) in the framework of the supersymmetric reduced minimal 3-3-1 model are investigated. In the DCH sector, we prove that there always exists a region of the parameter space where the mass of the lightest DCH is of the order of  GeV even when all other new particles are very heavy. The lightest DCH mainly decays to two same-sign leptons while the dominant decay channels of the heavy DCHs are those decaying to heavy particles. We analyze each production cross section for as a function of a few kinematic variables, which are useful to discuss the creation of DCHs in colliders as an indicator of new physics beyond the Standard Model. A numerical study shows that the cross sections for creating the lightest DCH can reach values of a few pb. The other two DCHs are too heavy, beyond the observable range of experiments. The lightest DCH may be detected by the International Linear Collider or the Compact Linear Collider by searching for its decay to a same-sign charged lepton pair.

H.N. Long

Signal of doubly charged Higgs at e e colliders